Electromagnetic control apparatus



April 12, 1960 R. B. MATTHEWS 2,

ELECTROMAGNETIC CONTROL APPARATUS Filed April 23, 1956 IN V EN TOR.

ATTORNEYS United States Patent 2,952,773 ELECTROMAGNETIC CONTROL APPARATUS Russell B. Matthews,

Wauwatosa, Wis, assignor to Base Inc., Milwaukee,

This invention relates to improvements in electromagnetic control apparatus, and more particularly to re lays affording a time delay in the operation thereof.

It is a general object of the present invention to provide in one form thereof a relay having contacts for controlling a load circuit, said relay being operable to actuate said contacts in response to energization of a winding of said relay, but only after a predetermined time delay following such energization, said relay being substantially instantaneously responsive to deenergization of its said winding to return said contacts in their initial position.

Another general object of the invention is to provide, in another form thereof, a relay which upon energization of a winding thereof instantaneously actuates the load controlling contacts, and upon deenergization of said winding affords a time delay before said contacts are returned to their initial positions.

It is a more specific object of the invention to provide an improved relay of the class described having a pair of energizing windings, and having a pair of movable armatures, one being act'uatable to an attracted position in response to energization of the first of said windings, and the other being actuatable to an attracted position in response to energization of the second of said windings, but only while said first mentioned armature is in attracted position, there being means responsive to attractive move ment of the first armature to efifect, after a predetermined time delay, energization of the second winding and thereby attractive movement of the second armature, and there being circuit controlling contacts positioned for actuation by attractive movement of said second arma' ture, deenergization of said first winding effecting sub stantially instantaneous retraction of both of said arma-.

tures and return movement of said contacts to their initial position.

Another specific object of the invention is to provide an improved relay of the class described wherein both of the armatures are actuatable to attracted position in response to energization of the first of said windings for immediate actuation of the circuit controlling contacts by said second armature, there being means responsive to attractive movement of the first armature to energize said second Winding, said means being operable to continue energization of said second winding for retention of said second armature in attracted position and thereby said contacts in actuated position for a predetermined period after deenergization of said first winding and corresponding dropout of said first armature.

Still another object of the invention is to provide an improved relay of the aforementioned character having an electromagnet frame member provided with two pair of pole pieces, one cooper'able with the first-armature, and the other cooperable with the second armature, said first and second windings being disposed on said first pair of pole pieces respectively, and said electromagnet frame providing with said first armature a low reluctance flux path for the flow of 'a'first density of flux generated by energization of one of said windings, ifiow through said flux path at a predetermined higher density level effecting saturation of a portion of said flux path and flux flow between said second pair of pole pieces and the second armature.

Another object of the invention is to provide an improved relay of the class described wherein the time delay energy source means comprises electrical heat generating means disposed in heating relation to the hot junction means of a thermoelectric generator connected in circuit with the second ener ing winding of the relay, the heat generated by the heat generating means heating said hot junction means suificiently to effect energization of said second Winding, and the time delay afforded thereby being adjustable.

Further objects and advantages of the invention will become apparent as the description proceeds, reference being had to the drawing accompanying and forming a part of this specification illustrating one form of the invention and in which like reference characters indicate the same parts in all of the views. In the drawing:

Figure .1 shows one form of the improved relay in plan view with the heat generating means and thermoelect ric generator together with all of the electrical connections to said relay being illustrated schematically;

Figure 2 is a side elevational view of the improved relay;

Figure 3 is a perspective view of the electromagnet frame utilized in the improved relay; and

Figure 4 shows another form of the improved relay in plan view similar to Figure 1.

Referring more particularly to Figures 1 to ,3 of the drawing, the form of the invention illustrated therein comprises a base plate ,or member 5 having upstanding apertured corner lugs 6 and 7. The base plate 5 is pref erably formed of non-magnetic material, for example aluminum, and suitably fixed on said plate is an electromagnet frame member .8 of magnetically permeable material. The frame 8 is generally H-shaped in plan view, the arms thereof being formed with upstanding pole pieces 9, 10, 11 and 12 as shown most clearly in Figure 3. The frame .8 is slotted, as at 13, to provide portions of reduced cross-section 14 and 15. As shown in Figure 1, an energizing winding 16 is wound on the pole piece 9, and an energizing winding 17 is wound on the pole piece 10, the latter windingalso being shown in Figure 2.

Pivotally mounted for movement to attracted and retracted positions with respect to the pole faces of the pole pieces 9 and 10 is a magnetically permeable armature 18. The aforementioned pivotal mounting maybe afforded by a bracket member 19 afiixed to said armature and provided with apertured lugs for receiving a shaft 21"! having its ends supported in the apertures of the upstanding lugs .6 of the base member 5. A magnetic permeable armature 21 is pivotally mounted for movement between retracted and attracted positions with respect to the pole faces of the pole pieces 11 and 12 and may be carried by .a bracket 2 provided with apertured lugs for receiving .a shaft 23 which, in turn, has its ends supported in the apertures in the upstanding lugs 7. The armature 18 carries an adjustable contact actuating screw 24, and the armature 21 carries a similar contactactuating screw 25, both of which may have insulating tip portions.

Suitably mountedon the base member 5 are a pair of normally open contact leaves 26 and 27, the leaf 26 being engaged by the actuating screw 24, and through said screw biasing the armature 18 toward its retracted positionshown in Figure 2. Similarly mounted on the base member '5 are a pair of normally open contacts '28 and .29, the contact 28 being engaged by the contact actuating .screw25, and .through said screw biasing the ure 2.

Referring to Figure l, the terminals of the winding 17 are connected to the terminals of an input source 30 by conductors 31 and 32. The terminals of the winding 16 are connected in circuit with a thermoelectric generator 33 by means of conductors 34 and 35. The thermoelectric generator 33 may take the form of one or more thermocouples having hot and cold junction means, the illustrated generator taking the form of a thermocouple. Positioned adjacent the hot junction of said thermocouple is heat generating means which may take the form of an electrical heating element 36, one terminal of which is connected in circuit with the contact 27 by means of a conductor 37, and theother terminal of which is connected in circuit with a source of electrical energy 38 by means of a conductor 39 which is also connected in circuit with one terminal of the load 4!) to be controlled by the improved relay. Contacts 26 and 28 are connected in circuit with the other terminal of the source 38 by means of a conductor 41, and the contact 29 is connected in circuit with the other terminal of the load 40 by means of a conductor 42.

The operation of the form of improved relay shown in Figures 1 to 3 will now be described. Upon energizetion of the winding 17 by current from the source 30 affording the input signal, flux is generated by said winding and flows within the pole piece in a direction dependent upon the polarity of said current. Assuming that the flux flow is downwardly within the pole piece 10, said flux then flows through the frame portions 14 and and upwardly through the pole piece 9, thence spanning the air gap between the pole pieces 9 and 10 and armature 18 to link said armature and actuate the latter to attracted position (not shown) with respect to the pole faces of said pole pieces against the bias of the contact leaf 26. This movement of the armature 18, through the screw 24, actuates the contact 26 into engagement with the contact 27 to complete the circuit between the source 38 and the heat generating means 36, whereupon the latter generates heat which is supplied to the hot junction means of the thermoelectric generator 33.

In response to the heat from the heat generating means 36, the thermoelectric generator 33 energizes the winding 16, which thereupon produces additional flux within the pole piece 9, which is of the same polarity as that produced in said pole piece by energization of the winding 17. The reduced cross-section portions 14 and 15 of the frame 8 are incapable of accommodating flux flow therethrough of all of the flux generated by energization of both of the windings 16 and 17, and as a result, said portions become saturated, and the flux which cannot flow through said portions is shunted to an alternative path, fiowing upwardly in the pole piece 12 and spanning the air gaps separating the armature 21 from the pole pieces 11 and 12 to link said armature and effect attractive movement thereof to its attracted position (not shown) against the bias of the contact leaf 28. This attractive movement, through the screw 25, effects controlling movement of the contact 28, actuating the latter into engagement with the contact 29 to thereby complete the energizing circuit between the source 38 and the load 40.

It will be observed that the generation of heat by the heat generating means 36 and the heating thereby of the hot junction means of the thermoelectric generator 33 sufficiently to energize the winding 16 requires a certain amount of time which introduces a time delay between the impression of the input signal effecting energization of the winding 17 and the actuation of the contact 28 into engagement with the contact 29 by attractive movement of the armature 21. This time delay may be adjusted by, varying the position of the hot junction means of the thermoelectric generator 33 with respect to the heat generatingmeans 36 or by changing magnitude of current flowing through said heat generating means, for example by adjustment of a variable resistance 43 interposed in the conductor 37. Ambient temperatures have little effect on the time delay thus afforded, since both the hot and cold junction means of the generator 33 are affected equally.

0n deenergization of the winding 17, both of the armatures 18 and 21 move to their retracted positions shown substantially instantaneously, to thereby open the energizing circuit to the heating element 36 as well as to the load 40 at the contacts 26 and 28 respectively. The cause of the retractive movement of the armature 21 is that the reduced sections 14 and 15 of the frame 3 are capable of accommodating the flux generated by the winding 16 alone, so that there is'no excess flux to be shunted through the pole pieces 11 and 12 to link the armature 21. The reason for the substantially simultaneous though sequential retraction of the armature 13 on deenergization of the winding 17 is that the structure is so designed that the flux generated in the winding 16 when the latter is energized by the thermoelectric generator 33 is insuflicient to hold the armature 18 in attracted position against the bias of the leaf contact 26.

Figure 4 illustrates another form of the improved relay which is constructed to afford instantaneous actuation of the load circuit controlling contacts in response to an energizing input signal, and to return said contacts to their initial position after a predetermined time delay following termination of said input signal.

The appearance of the form of the invention shown in Figure 4 resembles that of the form of the invention shown in Figure 1, except for certain of the electrical circuit connections. Parts indicated in Figure 4 by primed reference characters correspond to the parts of Figure 1 indicated by the same reference characters unprimed.

in Figure 4 the conductor 39 connects one terminal of the electrical resistance element 36' and one terminal of the load circuit 4% in circuit with one terminal of the source 38'. The other terminal of the load circuit 40 is connected in circuit with the contact 27 by a conductor 42'. A conductor 37 connects the other terminal of the heater element 36 in circuit with the contact 29' and may have interposed therein a variable resistance 43'. A branched conductor 41 connects the contacts 26' and 28' in circuit with the other terminal of the source 38.

The operation of the form of the invention shown in Figure twill now be described. The winding 17' is so designed that when an energizing input signal is impressed thereon at the terminals 30, said winding gencrates sufficient flux to effect pull-in of the armature 13', saturation of the portions 14' and 1-5 of the magnet frame 8, and pull-in of the armature 21. Pull-in of both of thearmatures 15 and 21 moves the contacts 26' and 28 into their circuit making positions with respect to the contacts 27' and 29', respectively. This contact movement immediately completes the circuit from the source 38 to the load circuit 49* through the conductor 41, contacts 26 and 27', conductor 42' and conductor 39'. This contact movement also completes the energizing circuit from the source 38 to the heater ele ment 36' through the conductor 41, contacts 23' and 29, variable resistor 43', and conductors 37' and 39'. The energized heater 36' heats the hot junction of the thermoelectric generator 33, the output of which energizes the winding 16, which thereupon generates a flux which aids that generated by the energized winding 17. This additional flux has no immediate effect, however, it being shunted through the armature 21' which is already in attracted position.

Termination of the energizing input signal at the terminals 30' deenergizes the winding 17' so that the only flux flowing in the magnetic circuit is that generated by amass the-winding l6". Sincethe restrictedportions 14 and 15' can accommodate all of the flux generated by the winding- 16', there is no excess flux for linkage-of the armature 21 and the latter drops out to open the circuit at the contacts 28' and 29. The flux generated by the winding 16' is su'tficient to hold the armature 18'- in attracted position, and therefore the contact 26 emains in circuit-making engagement with the contact 27'. Deenergization of the heater element 36' resulting from drop-out of the armature 21' permits said heater element and the generator 33' to cool. After a cooling period, the output of the generator 33' drops to a predetermined level, and the winding 16 no longer generates-suificient flux to hold in the armature 18", whereupon said armature drops out under the bias of the springcontact 26 which simultaneously moves to circuit-interrupting position and deenergizes the load circuit.

The time requiredfor the heater 36 andthe generator 33 to cool sufficiently to effect drop-out of the armature l8 afiords a time delay. between the termination of the input energizing signal at terminals30 and circuit interrupting movement of the contact 26. Thus, the relay shown in Figure 4 afiords instantaneous actuation of the load circuit controlling. contacts 26'-27', in response to an input signal, with return of said contacts to their initial position after a predetermined time delay following termination of said input signal.

The embodiments of the invention shown in the drawing are for illustrative purposes only, and it is to to be expressly understood that various changes and modifications may be made therein without departing from the spirit of the invention. The drawing and the accompanying specification are not to be construed as a definition of the limits or scope of-the invention, referencebeing had to the appended claims for that purpose.

What is claimed as the invention is:

1. A circuit controllingdevice, comprising an elec tromagnet having first and second energizing windings, a first armature cooperable with said electromagnet, said armature being biased toward a retracted position and movable toward an attracted position with respect to said electromagnet by energization of saidfirst winding, a second armature cooperable with said electromagnet, said second armature being biased toward a retracted position and movable toward an attracted position with respect to said electromagnct by energization of said second winding only while said first armature is in attracted position, time delay energy source means under the control of said first armature and connected in circuit with said second Winding, said source means being operable after a predetermined time delay foliowing movement ofsaid first armature to attracted position to energize said second winding and thereby efiect attractive movement of said second armature, and circuit controlling." contacts operatively associated with said second armature for'actuation from a first toward a second controlling position by attractive movement of said second armature, saidsecond winding when energized alone creating insufficient attractive force in said electromagnet to retain said armaturcs in attracted position, Wherefore dcenergization of said first Winding eifects substantially instantaneous retraction of both of said armatures for simultaneous return of said contacts to their first controlling position.

2. A circuit controlling device comprising an electromagnet having first and second energizing windings, a first armature cooperable with said electromagnet, said armature being biased toward a retracted position and movable toward an attracted position with respect to said electromagnet by energization of said first winding, a

econd armature cooperable with said electromagnet, saidsccond armature being biased toward a retracted position and movable toward an attracted position with respect to said electromagnet by energization of said second winding only while said-first armature is in attracted position, heatgenerating means rendered operative by movement of-said first armature to attracted position and inopera-- tive by retractile movement thereof, thermoelectric generator means subject to the heat of said heat generating means and connected in circuit with said second Winding for. venergizing the latter to effectattractive movement of said second armature, and circuit controlling contacts operativcly associated with said second armature for actuation from a first toward a second position by attractive movement of said second armature, the time re quired for said heat generating means to heat said thermoelectric generator means affording a time delay between energization of said first Winding and actuation of said contacts toward said second position, said second winding when energized alone creating insufficient attractive force in said electromagnet to retain said armatures in attracted position, wherefore deenergization of said first winding eifects substantially instantaneous retraction of both of said armatures for return of said contacts to their first position.

3. A circuit controlling device comprising an electromagnet having first and second energizing windings, a first armature cooperable with said electromagnet, said armature being biased toward a retracted position and movable toward an attracted position with respect to said electromagnet by energization of said first winding, a second armature cooperable with said electromagnet, said second armature being biased toward a retracted position and movable toward an attracted position with respect to said electromagnet by energization of said second winding only while said first armature is in attracted position, electroresponsive heat generating means, switch means in circuit with a source of electric energy and with said heat generating means completing the circuit therebetween when said first armature is in attracted position and interrupting said circuit by rctractile movement of said armature, thermoelectric generator means subject to the heat of said heat generating means and connected in circuit with said second winding for energizing the latter to effect attractive movement of said second armature, and circuit controlling contacts operatively associated with said second armature for actuation from a first toward a second position by attractive movement of said second armature, the time required for said heat gen erating means to heat said thermoelectric generator means affording a time delay between energization of said first winding and actuation of said contacts toward said second position, said second winding when energized alone creating insufiicient attractive force in said electromagnet to'retain said armatures in attracted position, wherefore deenergization of said first Winding elfects substan tially' instantaneous retraction of both of said arniatures for return of said contacts to their first position.

4. A time delay control device, comprising a magnetic member, a first magnetic control member having a re tracted controlling position relative to said magnetic member and having an attracted controlling position provid ing with said magnetic member a low reluctance flux path, flux generating means operable when energized by a first source to generate flux flow in said flux path at least at a first density level sufiicient to retain said first control member in attracted position, said fiux path having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level,

. time delay electric energy source means having first and second output levels in circuit with said flux generating means and operable at the higher of said output levels to supply energizing current which with the current from said first source causes said flux generating means to generate flux flow in said iiux path at least at said predetermined higher density levcl to cause flux to be shunted from said flux path adjacent said saturable portion, and a second magnetic control member positioned to be linked by said shunted fiux for movement'thereby from one to another controlling position, said time delay energy source means being opcratively'associated with one of said control members to effect a change in the output thereof from one to the other of said levels after a predetermined time delay following movement of said one control member from one to another of its controlling positions.

5. A time delay relay, comprising a magnetic member, a first magnetic control member having a retracted controlling position relative to said magnetic member and having an attracted controlling position providing with said magnetic member a low reluctance flux path, fiux generating means operable when energized by a first source to generate flux fiow in said flux path at least at a first density level sutlicient to retain said first control member in attracted position, said flux path having a portion which is saturable by fiux flow through said fiux path at less than a predetermined higher density level, time delay electric energy source means having first and second output levels in circuit with said flux generating means and operable at the higher of said output levels to supply energizing current which with the current from said first source causes said flux generating means to generate flux fiow in said flux path at least at said predetermined higher density level to cause flux to be shunted from said flux path adjacent said saturable portion, a second magnetic control member positioned to be linked by said shunted fiux for movement thereby from one to another controlling position, said time delay energy source means being operatively associated with one of said control members to effect a change in the output thereof from one to the other of said levels after a predetermined time delay following movement of said one control member from one to another of its controlling position, and circuit controlling contacts operatively associated with the other of said control members for.

actuation thereby.

6. A time delay control device, comprising a magnetic member, a first magnetic control member biased toward a retracted position relative to said magnetic member and having an attracted position providing with said magnetic member a low reluctance flux path, flux generating means operable when energized by a first source to generate flux flow in said flux path at a first density level sufficient to retain said first control member in attracted position against its bias, said flux path having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level, time delay electric energy source means having a first and a higher second output level in circuit with said flux generating means and operable at the higher of said output levels to supplyenergizing current which with the current from said first source causes said fiux generating means to generate flux flow in said flux path at least at said predetermined higher density level to cause flux to be shunted from said flux path adjacent said saturable portion, and a second magnetic control member biased toward a retracted position relative to said magnetic member wherein it can be linked by said shunted flux for movement thereby to an attracted position, said time delay energy source means being operatively associated with said first control member to effect a change in the output thereof from said first to said second level and thereby movement of said second control member from its retracted to its attracted position after a predetermined time delay following move ment of said first control member to its attracted position, failure of said source means effecting substantially instantaneous retraction of both of said control members under their bias.

7. A time delay relay, comprising a magnetic member, a first magnetic control member biased toward a retracted position relative to said magnetic member and having an attracted position providing with said magnetic member a low reluctance flux path, flux generating means operable when energized by a first source to generate fiux flow in said flux path at a first density level suificient to retain said first control member in attracted position against its bias, said fiu'x path having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level, time delay electric energy source means having a first and a higher second output level in circuit with said flux generating means and operable at the higher of said output levels to supply energizing current which with the current from said first source causes said fiux' generating means to generate flux flow in said flux path at least at said predetermined higher density level to cause flux to be shunted from said flux path adjacent said saturable portion, a second magnetic control member biased toward a retracted position relative to said magnetic member wherein it can be linked by said shunted flux for movement thereby to an attracted position, and circuit controlling contacts operatively associated with said second control member for actuation thereby, said time delay energy source means being operatively associated with said first controlmember to effect a change in the output thereof from said first to said second level and thereby movement of said second control member from its re tracted to its attracted position after a predetermined time delay following movement of said first control member to its attracted position, failure of said first source means effecting substantially instantaneous retraction of both of said control members under their bias. 1 8. A time delay control device, comprising a magnetic member, a first magnetic control member biased toward a retraoted'position relative to said magnetic member and havingan attracted position providing with said magnetic member a loW reluctance flux path, flux generating means operable when energized at a first level to generate fiux flow in said flux path at a first density level sufiicient to retain said first control member in attracted position against its bias, said flux path having a portion which is saturable by fiux flow through said fiux path at less than a predetermined higher density level, said fiux generating means being operable when energized at a second higher level to generate flux flow in said flux path at said predetermined higher density level, time delay electric energy source means in circuit with said flux generating means and having an operating output sufiicient to energize said flux generating means at said first level, first source means for energizing said flux generating means at said second level to cause said flux generating means to generate fiuv flow in said flux path at said predetermined higher density level to efiect attractive movement of said first control member and shunting of flux from said flux path adjacent said saturable portion, and a second magnetic control member biased towand a retracted position relative to said magnetic member wherein it can be linked by said shunted flux for movement thereby to an attracted position, said time delay energy source means being operatively associated with said second control member, failure of said first source means .efiecting retraction of said second control member, in response to which said time delay source means maintains said flux generating means energized at said first level for a predetermined period after which the output thereof drops ed to permit retraction of said first control member.-

9. A time delay relay, comprising a magnetic member, a first magnetic control member biased toward a retracted position relative to said magnetic member and having an attracted position providing with said magnetic member a low reluctance flux path, circuit controlling contacts operatively associated with said first control member for actuation thereby, flux generating means operable when energized at a first level torgenerate flux flow in said fiux path at a first density level sufiicient to retain said first control member in attracted position against its bias, said flux path having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level, said flux generating means being operable when energized at a second higher level to generate flux flow in said flux path at said predetermined higher density level, time delay electric energy source means in circuit with said flux generating means and having an operating output sufiicient to energize said flux generating means at said first level, first source means for energizing said flux generating means at said second level to cause'said flux generating means to generate flux flow in said flux path at said predetermined higher density level to effect attractive movement of said first control member and shunting of flux from said flux path adjacent said saturable portion, and a second magnetic control member biased toward a retracted position relative to said magnetic member wherein it can be linked by'said shunted flux for movement thereby to an attracted position, said time delay energy source means being operatively associated with said second control member, failure of said first source means effecting retraction of said second control member, in response towhich said time delay source means maintains said flux generating means energized at said first level for a predetermined period after which the output thereof drops ofi to permit retraction of said first control member.

10. A time delay control device comprising a magnetic member, a first magnetic control member having a retractedv controlling position relative to said magnetic member and having an attracted controlling position providing with said magnetic member a low reluctance flux path, flux generating means operable when energized from a first source to generate flux flow in said flux path at least at a first' density level sufiicient to retain said first control member in attracted position, said flux path having a portion which is saturable by flow therethrough of threat less than a predetermined higher density level, heat generating means, thermoelectric generator means subject to the temperature at saidheat generating means and connected in circuit with said fiux' generating means, said generator when heated being operable with said first source to cause said flux generating means to generate flux flow in said flux path at least at said predetermined higher density level, to cause flux to be shunted from said flux path adjacent said saturable portion, and a magnetic second control member positioned to be linked by said shunted fiux'for movement thereby from one to another controlling position, said' heat generating means being operatively associated with one of said control members to efiect a change in the temperature at said heat generating means from a first to a second level after a predetermined time delay following movement of said one'control member from one to another of its controlling positions.

11. A time delay relay comprising a magnetic memher, a first magnetic control member having a retracted controlling position relative to said magnetic member and having an attracted controlling. position providing with said magnetic member a low reluctance flux path, flux generating means operable when energized from a first source to generate flux flow in said flux path at least at a first density level sufficient to retain said first control member in attracted position, said flux path having a portion which is saturable by flow therethrough of flux at less than a predetermined higher density level, heat generating means, thermoelectric generator means'subject to the temperature at said heat generating means and connected in circuit with said flux generating means, said generator when heated being operable with said first source to cause said flux generating means to generate flux how in said flux path at least at'said predetermined higher density level, to cause flux to be shunted from said flux path adjacent said saturable portion, a magnetic second control member positionedto be linked by said shunted flux formovement thereby from one to another controlling position, said heat generating means being operatively associated with one of said control members to effect a change in the temperature at'said heat generating. means from a firsttoa second level after a predetermined time delay following movement of said one con trol member from one to another of its controlling positions, and circuit controlling contacts operatively associated with the other of said control members for actuation thereby.

12. A time delay relay comprising a magnetic member, a first magnetic control member having a retracted controlling position relative to said magnetic member and having an attracted controlling position providing with said magnetic member a low reluctance flux path, flux generating means oper-able'when energized from a first source to generate flux flow in said flux path at least at a first density level sufiicient to retain said first control member in attracted position, said flux path having a portion which is saturable by flow therethrough of flux at less than a predetermined higher density level, heat generating means, thermoelectric generator means subject to the temperature at said heat generating means and connected in circuit with said fiux generating means, said generator when heated being operable with said first source to cause said flux generating means to generate flux flow insaid fiuxpathat least at said predetermined higher density level, to cause ilux to be shunted from said flux path adjacent said saturable portion, a magnetic second control member positioned to be linked by said shunted fiux for movement thereby from one to another controlling position, said heat generating means being operatively associated with said first control member to raise the temperature atsaid heat generating means from a first to a higher level and thereby efiect heating of said generator and movement of said secondcontrol member to its said other controlling positon after a predetermined time delay following movement of said first control member from one to another of its controlling positions, and circuit controlling contacts operatively associated with said second control member for actuation thereby.

13. A time delay relay comprising a magnetic member, a lrst magnetic control member having a retracted controlling position relative to said magnetic member and having an attracted controlling position providing with said magnetic member a low reluctance flux path, flux generating means operable when energized from a first source to generate flux flow in said flux path at least at a first density level sufficient to'retain said first control member in attracted position, said flux path having a portion which is saturable by flow therethrough of flux at less than a predetermined higher density level, heat generating means, thermoelectric generator means subject to the temperature at said heat generating means and connected in circuit with said flux generating means, said generator when heated to a first'level being operable with said first source to cause said flux generating means to generate fiux flow in said flux path at least at said predetermined higher density level, to cause flux to be shunted from said flux path adjacent said saturable portion, a magnetic second control member positioned to be linked by said shunted flux for movement thereby from one to another controlling position, said generator also being operable when heated to said first level to alone cause said flux generating means to generate flux flow in said flux path at said first density level said heat generating means being operatively associated with said second control member to generate heat and raise the temperature at said heat generating means from a lower to said first level in response to movement of said second control member from its said one to its said another'controlling position, said heat generating means being rendered inoperative by return of said second control member to its said one controlling position in response to failure of said first source, wherefore the temperature at said generator, after a predetermined time delay following return of said second control member to its said one controlling position, drops from said first to said lower level, permitting return of said first control member to its retracted position, and- 11 a circuit controlling contacts operatively associated with said first control member for actuation thereby.

14. A time delay control device, comprising an electromagnet having a magnetically permeable frame and having a pair of flux generating windings, a first armature biased toward a retracted position and movable to an attracted position providing with said frame'a low reluctance fiux path, a first source in circuit with one of said windings and operable to supply an energizing current causing said winding to generate flux flow in said flux path at least at a first density level suflicient to retain said first armature in attracted position against its bias, said frame having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level, time delay electric energy source means having first and second output levels in circuit with the other of said windings and operable at the higher of said output levels'to supply energizing current to said other winding such that said winding together with said first winding when energized generate flux flow in said flux path at least at said predetermined higher density level to cause flux to be shunted from said frame adjacent said saturable portion, and a second armature biased toward a retracted position with respect to said frame wherein it can be linked by said shunted flux for movement thereby to attracted position against its bias, said time delay energy source means being operatively associated with one of said armatures such that the output thereof is changed from one to the other of said levels after a predetermined timedelay following movement of said one armature from one to another of its positions.

15. A time delay relay, comprising an electromagnet having a magnetically permeable frame and having a pair of flux generating windings, a first armature biased toward a retracted position and movable to an attracted position providing with said frame a low reluctance flux path, a first source in circuit with one of said windings and operable to supply an energizing current causing said winding to generate flux flow in said flux path at least at a first density level sufiicient to retain said first armature in attracted position against its bias, said frame having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level, heat generating means, thermoelectric generator means subject to the temperature at said heat generating means and connected in circuit wtih the other of said windings, said generator when heated being operable to supply energizing current to said other winding such that said winding together with said first winding energized by said first source generate flux flow in said fiux path at least at said predetermined higher density level to cause flux to be shunted from said frame adjacent said saturable portion, a second armature biased toward a retracted position with respect to said frame wherein it can be linked by said shunted fiux for movement thereby to an attracted position against its bias, said heat generating means being operatively associated with and controlled by one of said armatures to effect a change in the temperature at said heat generating means from one to another level after a predetermined time delay following movement of said one armature from one to another of its positions, and circuit controlling contacts operatively associated with the other of said armatures for actuation thereby.

16. A time delay relay, comprising an electromagnet having a magnetically permeable frame and having a pair of fiur generating windings, a first armature biased toward a retracted position and movable to an attracted position providing with said frame a low reluctance flux path, a first source in circuit with one of saidjwindings and operable to supply an energizing current causing said winding to generate flux flow in said flux path at least at a first density level sufficient to retain said first armature in attracted position against its bias, said frame having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level, electroresponsive heat generating means, thermoelectric generator means subject to the temperature at said heat generating means and connected in circuit with the other of said windings, said generator when heated being operable to supply energizing current to said other winding such that said winding together with said first winding energized by said first source generate flux flow in said flux path at least at said predetermined higher density level to cause flux to be shunted from said frame adjacent said saturable portion, a second armature biased toward a retracted position with respect to said frame wherein it can be linked by said shunted flux for movement thereby to an attracted position against its'bias, electrical contacts in circuit with a source of electrical energy and with said heat generating means for controlling the energization of the latter, said contacts being positioned for actuation by one of said armatures to effect a change in the temperature at said heat generating means from one to another level after a predetermined time delay following movement of said one armature from one to another of its positions, and circuit controlling contacts operatively associated with the other of said armatures for actuation thereby.

17. A time delay relay, comprising an electromagnet having a magneticallypermeable frame and having a pair of fiux generating windings, a first armature biased toward a retracted position and movable to an attracted position providing with said'frame a low reluctance flux path, a first source in circuit with one of said windings and operable to supply an energizing current causing said winding to generate flux fiow in said flux path at least at a first density level sufficient to retain said first armature in attracted position against its bias, said frame having a portion which is saturable by flux flow through said flux path at less than a predetermined higher density level, electroresponsive heat generating means, thermoelectric generator means subject to the temperature at said heat gencrating means and connected in circuit with the other of said windings, said generator when heated to a prede termined temperature being operable to supply energizing current to said other winding such that said wind ing together with .said first winding energized by said first source generate flux flow in said flux path at least at said predetermined higher density level to cause flux to be shunted from said frame adjacent said saturable portion, a second armature biased toward a retracted position with respect to said frame wherein it can be linked by said shunted flux for movement thereby to an attracted position against its bias, electrical contacts in circuit with a source of electrical energy and with said heat generating means for controlling the energization of the latter, said contacts being positioned for actuation by said first armature to effect energizationof said heat generating means and heating in the temperature of said thermoelectricgencrator to said predetermined temperature and attractive movement of said second armature after a predetermined time delay following movement of saidfirst armature from retracted to attracted position, and circuit controlling contacts operatively associated with said second armature for actuation thereby.

: 18. A time delay relay, comprising an electromagnet having a magnetically permeable frame and having a pair of flux generating windings, a first armature biased toward a retracted position and movable to an attracted position providing with said frame a low reluctance flux path, a firstsource in circuit with one of said windings and operable to supply an energizingcurrent causing said winding to generate flux flow in said flux path at least at a first densitydevel sufiicientto retain gsaid first armature in attracted position against its bias, said frame having a portion which is saturable by flux flow through said flux" path at less than a predetermined higher density level, electroresponsive heat generating means, thermoelectric generator means subject to the temperature at said heat generating means and connected in circuit with the other 13 of said windings, said generator when heated to a predetermined temperature being operable to supply energizing current to said other winding such that said winding together with said first winding energized by said first source generate flux flow in said flux path at least at said predetermined higher density level to cause flux to be shunted from said frame adjacent said saturable portion, a second armature biased toward a retracted position with respect to said frame wherein it can be linked by said shunted flux for movement thereby to an attracted position against its bias, said generator when heated to said predetermined temperature being operable to alone cause said flux generating means to generate flux flow in said flux path at said first density level, electrical contacts in circuit with a source of electrical energy and with said heat generating means for controlling the energization of the latter, said contacts being positioned for actuation by said second armature to effect energization of said heat generating means and heating of said thermoelectric generator to said predetermined temperature in response to attractive movement of said second armature, and deenergization of said heat generatingv means and cooling of said thermoelectric generator from said predetermined temperature to efiect retractile movement of said first armature after a predetermined time delay following movement of said second armature from attracted to retracted position in response to failure of said first source, and circuit controlling contacts operatively associated with said first armatures for actuation thereby.

References Cited in the file of this patent UNITED STATES PATENTS 1,516,646 Roseby Nov. 25, 1924 2,211,701 McGrath Aug. '13, 1940 2,266,185 Fillo Dec. 16, 1941 2,428,568 Hill Oct. 7, 1947 2,434,433 Ray Jan. 13, 1948 

